Commercially useful copper base alloys should possess a combination of high strength and high electrical conductivity for most applications. Unfortunately, the methods and elements previously utilized to provide an increase in one of these properties do so at the detriment of the other property. For example, elements such as zirconium and chromium have been used as additions to copper base alloys to provide this desirable combination of high strength and high electrical conductivity. The precipitation of chromium in copper is known to give large increases in strength and electrical conductivity over the values for the solid solution of copper and chromium. The precipitation hardened alloys containing chromium in copper have lower electrical conductivity but higher strength than pure copper. Precipitation of zirconium in copper is known to give large increases in electrical conductivity but only small increases in strength properties over the values for the solid solution of zironium in copper. Zirconium also significantly raises the recrystallization temperature of copper. These alloys have lower electrical conductivity properties than pure copper but a much better resistance to softening at high temperatures than pure copper.
Vanadium has recently been utilized to provide the combination of high strength and high electrical conductivity. For example, copending application Ser. No. 652,997 filed Jan. 28, 1976 discusses the effects of adding vanadium to copper base alloys containing chromium and zirconium. Russian Pat. No. 185,068 also discloses copper base alloys that contain chromium, zirconium and vanadium. This patent does not teach any processing steps for this alloy combination.
The present invention is an attempt to overcome the shortcomings of the alloy system described above by combining niobium with copper base alloys containing chromium and zirconium in order to increase the electrical conductivity of the alloys without detrimentally affecting the strength or hardness properties of said alloys.
Accordingly, it is a principal object of the present invention to provide an alloy system which is capable of improving the electrical conductivity without lowering the strength properties of said alloy system.
It is an additional object of the present invention to provide a process for treating the alloy system as aforesaid to develop the electrical conductivity and strength properties thereof.
Further objects and advantages of the present invention will become more apparent from a consideration of the following specification.